JP7838618B2 - Vehicle exterior components - Google Patents

Description

This invention relates to vehicle exterior components and vehicle exterior components equipped with far-infrared cameras.

In recent years, various sensors have been automatically installed in automobiles to improve safety. Examples of sensors installed in automobiles include cameras, LiDAR (Light Detection and Ranging), millimeter-wave radar, and infrared sensors.

Infrared radiation is classified into near-infrared (e.g., wavelengths 0.7 μm to 2 μm), mid-infrared (e.g., wavelengths 3 μm to 5 μm), and far-infrared (e.g., wavelengths 8 μm to 13 μm) based on its wavelength range. Infrared sensors for detecting these wavelengths include touch sensors, near-infrared cameras, and LiDAR for the near-infrared range; gas analysis and mid-infrared spectroscopy (functional group analysis) for the mid-infrared range; and night vision and thermal viewers (hereinafter referred to as far-infrared cameras) for the far-infrared range.

Automotive windows typically do not transmit far-infrared rays with wavelengths of 8 μm to 13 μm. Therefore, far-infrared cameras have traditionally been installed outside the vehicle, such as in the front grille, as described in Patent Document 1. However, installing far-infrared cameras outside the vehicle requires a more complex structure to ensure robustness, water resistance, and dust resistance, leading to higher costs. While installing a far-infrared camera inside the vehicle, specifically within the wiper's operating area, would solve these problems by protecting the camera from the window glass, the issue of far-infrared transmittance through window glass has prevented conventional placement of far-infrared cameras inside the vehicle.

Patent Document 2 discloses a window member in which a through-hole is made in a part of the window glass and an infrared-transmitting material is filled into the through-hole, in order to meet the above requirements.

U.S. Patent Application Publication No. 2003/0169491 UK Patent Application Publication No. 2271139

In window members like the one shown in Patent Document 2, if the through-hole is too large, it leads to a decrease in the strength of the window member and an increase in the amount of infrared-transmitting material used for filling, thus increasing costs. On the other hand, if the through-hole is too small, the amount of far-infrared radiation reaching the far-infrared camera decreases, resulting in reduced brightness and blurring in the resulting thermal image. In other words, the clarity of the thermal image decreases. However, Patent Document 2 did not sufficiently examine the size of the through-hole, and therefore, a specific configuration of a window member that has sufficient strength, cost, and field of view for a far-infrared camera for practical use has not yet been clarified.

In view of the above, the present invention aims to provide vehicle exterior components such as window members that are excellent in strength and cost, and that also ensure sufficient clarity of thermal images obtained by a far-infrared camera.
Furthermore, the objective is to provide a vehicle exterior component equipped with a far-infrared camera, in which a far-infrared camera is attached to the vehicle exterior component.

The present invention, which solves the above problems, is a vehicle exterior member that is attached to a vehicle equipped with a far-infrared camera and has a light-shielding region, further comprising a far-infrared transmitting region having an opening and a far-infrared transmitting member disposed within the opening, wherein the far-infrared transmitting member has an average transmittance of far-infrared rays with wavelengths of 8 to 13 μm of 25% or more, the length of the longest straight line connecting any two points on the outer surface of the far-infrared transmitting member is 80 mm or less, the diameter of the largest circle formed inside the projection diagram obtained by projecting the far-infrared transmitting member in the direction of the optical axis of the far-infrared camera is 12 mm or more, and the average thickness of the far-infrared transmitting member is 1.5 mm or more.
In one aspect of the present invention, the vehicle exterior member may be a vehicle window member.
In one aspect of the present invention, the vehicle exterior member may be an exterior member for the pillar of a vehicle.
In one embodiment of the vehicle exterior component of the present invention, the far-infrared transmitting member may be made of at least one material selected from the group consisting of ZnS, Ge, Si, and chalcogenide glass.
In one embodiment of the vehicle exterior member of the present invention, the outer surface of the far-infrared transmitting member is provided with 3 to 12 layers of anti-reflective coating, and the outermost layer of the anti-reflective coating may be a diamond-like carbon film.
In one embodiment of the vehicle exterior member of the present invention, the outer surface of the far-infrared transmitting member may be formed flush with the outer surface of the light-shielding region.
In one embodiment of the vehicle exterior component of the present invention, the far-infrared transmitting member may be attached with a urethane-based adhesive and/or an acrylic-based adhesive.
In one embodiment of the vehicle exterior member of the present invention, the area of the opening on the interior surface may be smaller than the area of the opening on the exterior surface.
In one embodiment of the vehicle exterior member of the present invention, the light-shielding region may further include a visible light-transmitting region having a visible light transmittance of 70% or more.
Furthermore, the vehicle exterior member with a far-infrared camera of the present invention comprises the vehicle exterior member of the present invention and a far-infrared camera, the far-infrared camera being mounted on the vehicle exterior member so as to be able to capture thermal images of the outside through the far-infrared transmission region.
One embodiment of the vehicle exterior member with a far-infrared camera of the present invention comprises the vehicle exterior member of the present invention, a far-infrared camera, and a visible light camera, wherein the far-infrared camera is mounted on the vehicle exterior member so as to be able to capture an external thermal image through a far-infrared transmitting member, and the visible light camera may be mounted on the vehicle exterior member so as to be able to capture an external image through a visible light transmitting region.
In one embodiment of the present invention, the optical axis of the far-infrared camera and the optical axis of the visible light camera are substantially parallel, and the distance between these optical axes may be 20 cm or less.
In one embodiment of the present invention, a vehicle exterior member equipped with a far-infrared camera, the visible light camera is a stereo camera comprising a first camera and a second camera, and the far-infrared camera may be located between the first camera and the second camera.
In one embodiment of the present invention, the far-infrared camera is attached to the vehicle exterior member via a bracket, and the inside of the bracket may be kept under vacuum or filled with thermal insulation material.
In one embodiment of the present invention, the far-infrared camera is mounted to the vehicle exterior member via a bracket, and may further include a temperature controller for adjusting the temperature inside the bracket.

According to the present invention, a vehicle exterior component such as a window member is provided that is excellent in strength and cost, and furthermore, ensures sufficient clarity of thermal images obtained by a far-infrared camera. Furthermore, a vehicle exterior component with a far-infrared camera is also provided, in which a far-infrared camera is attached to the vehicle exterior component.

Figure 1 is a schematic plan view of one embodiment of the vehicle exterior member of the present invention. Figure 2 is a cross-sectional view along the line A-A in Figure 1. Figure 3 is a schematic cross-sectional view of one embodiment of the vehicle exterior member of the present invention. Figure 4 is a schematic cross-sectional view of one embodiment of the vehicle exterior member of the present invention. Figure 5 is a schematic cross-sectional view illustrating the positional relationship between a vehicle exterior component and a far-infrared camera according to one embodiment of the present invention. Figure 6 is a schematic diagram illustrating the projection view in Figure 5. Figure 7 is a schematic cross-sectional view illustrating the positional relationship between a vehicle exterior component and a far-infrared camera according to one embodiment of the present invention. Figure 8 is a schematic cross-sectional view illustrating the positional relationship between a vehicle exterior component and a far-infrared camera according to one embodiment of the present invention. Figure 9 is a schematic cross-sectional view of one embodiment of the exterior component for a vehicle equipped with a far-infrared camera according to the present invention. Figure 10 shows the infrared transmission spectra of far-infrared transmitting members B, D, F, H, I, and J in the embodiment. Figure 11 is a thermal image showing the positional relationship with pedestrians in the test (thermal image visual evaluation) conducted in the example. Figure 12 shows thermal images of pedestrians extracted in the tests (thermal image visual evaluation) conducted in the examples, specifically in Example 1 (α = 30° and 60°), Example 5 (α = 30°), Example 10 (α = 30° and 45°), Example 12 (α = 30°), Example 13 (α = 30°), and Example 15 (α = 30°).

The embodiments of the present invention will be described below. However, the present invention is not limited to the embodiments described below. Furthermore, the embodiments shown in the drawings are schematic for the purpose of clearly illustrating the present invention and do not necessarily accurately represent the actual size or scale.

Figure 1 shows a schematic plan view of one embodiment of the vehicle exterior member of the present invention, and Figure 2 shows a cross-sectional view along the line A-A in Figure 1. The vehicle exterior member according to this embodiment is a window member applied to the windshield of a vehicle, and in particular is a window member attached to a vehicle equipped with a far-infrared camera.
Furthermore, the embodiments of the vehicle exterior member of the present invention are not limited to window members applied to the windshield of a vehicle. For example, they may be window members applied to the rear window or side window, or they may be other than window members, such as exterior members for pillars.

The glass substrate 2 constituting the window member 1 in this embodiment may be single-pane glass or laminated glass. Furthermore, the glass substrate 2 may be subjected to strengthening treatments such as physical strengthening or chemical strengthening.

The window member 1 of this embodiment includes a light-shielding area 3. Typically, the window member 1 has a light-transmitting area 4 in the center to ensure the driver's field of view, surrounded by a light-shielding area 3. Furthermore, while far-infrared cameras and other sensors are usually mounted on the upper part of the window member 1, as shown in Figure 1, a light-shielding area 3 is also provided around these mounting locations. This provision of light-shielding areas 3 is preferable because it protects the various sensors from sunlight. It is also preferable from an aesthetic standpoint because the wiring of the various sensors becomes invisible from outside the vehicle.

The light-shielding region 3 is formed by providing a light-shielding layer 5 on the glass substrate 2 that constitutes the window member 1. In other words, the light-shielding region 3 is the region in the glass substrate 2 that has the light-shielding layer 5 when viewed from above.
As the light-shielding layer 5, for example, a ceramic light-shielding layer or a light-shielding film can be used. As the ceramic light-shielding layer, for example, a ceramic layer made of conventionally known materials such as a black ceramic layer can be used. As the light-shielding film, for example, a light-shielding polyethylene terephthalate (PET) film, a light-shielding polyethylene naphthalate (PEN) film, a light-shielding polymethyl methacrylate (PMMA) film, etc. can be used.
The light-shielding layer 5 is usually formed on the inner surface of the glass substrate 2, but it may also be formed on the outer surface, and if the glass substrate 2 is laminated glass, it may be formed in the middle of the two panes of glass that make up the laminated glass.

Furthermore, the window member 1 of this embodiment includes a far-infrared transmitting region 6 within the light-shielding region 3.
The far-infrared transmitting region 6 is a region having an opening 7 formed within the light-shielding region 3 and a far-infrared transmitting member 8 placed within the opening 7.

If the average transmittance of far-infrared rays in the wavelength range of 8 to 13 μm of the far-infrared transmitting member 8 is less than 15%, the far-infrared transmittance of the far-infrared transmitting region 6 will be insufficient, and the performance of the far-infrared camera will not be fully realized. Therefore, in this embodiment, the average transmittance of far-infrared rays in the wavelength range of 8 to 13 μm of the far-infrared transmitting member 8 should be 25% or higher, preferably 40% or higher, more preferably 50% or higher, even more preferably 70% or higher, and particularly preferably 85% or higher. Note that an anti-reflective coating is essential to improve the average transmittance of far-infrared rays to 85% or higher.

The material of the far-infrared transmitting component is not particularly limited as long as it satisfies the above transmittance requirements, but examples include ZnS, Ge, Si, and chalcogenide glass.
Preferred compositions for chalcogenide glass include:
Expressed in atomic percentage,
Ge + Ga; 7% to 25%
Sb; 0% to 35%,
Bi; 0% to 20%,
Zn; 0% to 20%,
Sn: 0% to 20%,
Si; 0% to 20%,
La: 0% to 20%,
S+Se+Te; 55% to 80%,
Ti; 0.005% to 0.3%,
Li + Na + K + Cs; 0% to 20%,
The composition contains F + Cl + Br + I in amounts of 0% to 20%. Furthermore, it is preferable that this glass has a glass transition temperature (Tg) of 140°C to 550°C.

The method for attaching the far-infrared transmitting member 8 to the opening 7 is not particularly limited, but it can be attached using an adhesive such as a urethane-based adhesive and/or an acrylic-based adhesive. Generally, because the difference in thermal expansion between the automobile window glass and the far-infrared transmitting member is large, it is preferable to select an adhesive that can mitigate this difference and also has excellent adhesive strength, impact resistance, and environmental resistance. To improve environmental resistance, the adhesive surface on the outside of the vehicle may be protected with resin or the like.

A gap of 0.2 to 1.5 mm is preferably present between the far-infrared transmitting member 8 and the opening 7. If the gap is less than 0.2 mm, the difference in thermal expansion between the automobile window glass and the far-infrared transmitting member may cause optical distortion of the window glass or damage to the window glass and/or the far-infrared transmitting member. The gap is more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. On the other hand, if the gap exceeds 1.5 mm, the adhesive strength and impact resistance may be compromised. The gap is more preferably 1.2 mm or less, and even more preferably 1.0 mm or less.

The outer surface of the far-infrared transmitting member 8 is preferably formed flush with the outer surface of the light-shielding region 3, as shown in Figure 2. If it is not formed flush with the outer surface, for example, when applied to a vehicle's windshield, the wiper's wiping effect may be impaired. Furthermore, when applied to surfaces other than the windshield, the presence of a step may impair the vehicle's design, and dust and other debris may accumulate in the step. In addition, it is preferable that the far-infrared transmitting member is molded to match the curved shape of the vehicle's exterior component to which it is applied. The molding method for the far-infrared transmitting member is not particularly limited, but polishing or mold molding may be selected depending on the curved shape and the component.

The far-infrared transmitting member 8 may have a coating on its outer or inner surface. For example, an anti-reflective coating may be provided on the outer surface, the inner surface, or both sides, i.e., at least one of the outer surface and the inner surface. As the anti-reflective coating, 1 to 12 layers of anti-reflective coating are preferred, _and the material _is not particularly limited, _but Ge, Si, ZnS, ZnSe, _As₂S₃ , _As₂Se₃ , metal oxides ( _Al₂O₃ , _Bi₂O₃ , _CeO₂ , CuO, _HfO₂ , MgO, _SiO , _SiO₂ , TiO, _TiO₂ , _Ti₂O₃ , _Y₂O₃ , _ZrO₂ ), carbon hydride, diamond-like carbon (DLC), and metal fluorides ( _MgF₂ , _CaF₂ , _SrF₂ , _BaF₂ , _PbF₂ , _LaF₃ , _YF₃ ). From the viewpoint of scratch resistance, the outermost layer of the vehicle _is preferably a film _with a Mohs hardness of 7 or higher and high far-infrared transmittance. It is particularly preferable that the outermost layer of the vehicle be a diamond-like carbon film.

The shape of the far-infrared transmitting member 8 is not particularly limited, but it is preferably a plate-like shape that matches the shape of the opening 7. That is, for example, if the opening 7 is circular, it is preferable that the far-infrared transmitting member 8 be disc-shaped (cylindrical).
Furthermore, as shown in Figure 3, in the window member 1 of this embodiment, it is preferable that the area of the opening 7 on the inner surface is smaller than the area of the opening 7 on the outer surface, and that the shape of the far-infrared transmitting member 8 is also made such that the area on the inner surface is smaller than the area on the outer surface. By adopting such a configuration, the strength against impacts from the outside of the vehicle is improved. As shown in Figure 4, if the glass substrate of the window member of this embodiment is laminated glass comprising a first glass 2a (outer surface) and a second glass 2b (inner surface), then the area of the opening 7a of the first glass 2a should be made larger than the area of the opening 7b of the second glass 2b, and the far-infrared transmitting member 8, which matches the size of the opening 7a of the first glass 2a, should be placed inside the opening 7a of the first glass 2a.
Furthermore, from the standpoint of strength, the thickness of the far-infrared transmitting member 8 should be 1.5 mm or more, preferably 2.0 mm or more, and more preferably 3.0 mm or more. As long as the average transmittance of far-infrared rays with wavelengths of 8 to 13 μm is ensured, there is no particular upper limit to the thickness of the far-infrared transmitting member 8, but it is usually 5.0 mm or less.
Furthermore, the far-infrared transmitting member may be made in the shape of a lens in order to achieve both a wider field of view of the far-infrared camera and improved mechanical properties. This configuration is preferable because it allows for efficient collection of far-infrared light even with a small area of the far-infrared transmitting member. In this case, the number of lens-shaped far-infrared transmitting members is preferably one to three, and typically two. Moreover, it is particularly preferable that the lens-shaped far-infrared transmitting member be pre-aligned and modularized, and integrated with a housing or bracket that adheres the far-infrared camera to the exterior of the vehicle.

If the outer surface of the far-infrared transmitting member 8 is too large, the strength of the window member will be insufficient. Therefore, in this embodiment, the length of the longest straight line connecting any two points on the outer surface of the far-infrared transmitting member 8 should be 80 mm or less, preferably 70 mm or less, and more preferably 65 mm or less. Note that if the outer surface of the far-infrared transmitting member 8 is circular, this length corresponds to the diameter.

Furthermore, the amount of far-infrared radiation reaching the far-infrared camera attached to the window member 1 of this embodiment depends on the size of the largest circle among the circles formed inside the projection diagram obtained by projecting the far-infrared transmitting member 8 in the direction of the optical axis of the far-infrared camera. This will be described in detail below with reference to the drawings.
Figure 5 is an enlarged cross-sectional view of the area around the far-infrared transmitting region 6 in the window member 1. The window member 1 is usually mounted on the vehicle at a predetermined angle α with respect to the horizontal direction H. On the other hand, the far-infrared camera 9 is usually mounted so that its optical axis X is approximately horizontal. Therefore, the amount of far-infrared radiation reaching the far-infrared camera 9 depends not only on the size of the far-infrared transmitting member 8 but also on this inclination angle α. Considering this, when examining the amount of far-infrared radiation reaching the far-infrared camera 9, it is appropriate to examine the size of the projection diagram 11 obtained by projecting the far-infrared transmitting member 8 onto a projection surface 10 perpendicular to the optical axis X in the direction of the optical axis X of the far-infrared camera 9. Furthermore, since the field of view of the far-infrared camera 9 is usually circular, it is appropriate to examine the size of the largest circle 12 among the circles formed inside the projection diagram 11. Figure 6 shows a schematic diagram illustrating the projection diagram 11 projected onto the projection surface 10 in Figure 5, and the largest circle 12 among the circles formed inside the projection diagram 11.
The inventors conducted repeated experiments and found that if the diameter of the largest circle 12 among the circles formed inside the projection diagram 11 is less than 12 mm, the amount of far-infrared radiation reaching the far-infrared camera 9 decreases, resulting in a decrease in brightness and blurring in the obtained thermal image, and insufficient clarity of the thermal image cannot be ensured.
Therefore, in the window member 1 of this embodiment, the diameter of the largest circle 12 among the circles formed inside the projection diagram 11 obtained by projecting the far-infrared transmitting member 8 in the optical axis X direction of the far-infrared camera 9 is set to 12 mm or more, preferably 20 mm or more, and more preferably 30 mm or more.
Furthermore, the projection diagram 11 obtained by projecting the far-infrared transmitting member 8 in the optical axis X direction of the far-infrared camera 9 refers to the figure obtained by projecting the shape of the outer surface of the far-infrared transmitting member 8 onto a plane perpendicular to the optical axis X in the direction of the optical axis X.

Furthermore, although it depends on the size of the far-infrared transmitting member 8 and the thickness of the glass substrate 2, if the angle α of the inclination of the window member 1 of this embodiment with respect to the horizontal direction when attached to the vehicle is too small, the following problems will occur. Specifically, if the angle α is too small, when the window member 1 is observed in a direction parallel to the optical axis X, the area that has only the far-infrared transmitting member 8, that is, the area that does not have the glass substrate or light-shielding layer (area Y in Figure 7) will be small. If this area Y is too small, there is a risk that the clarity of the thermal image obtained by the far-infrared camera cannot be sufficiently ensured. Therefore, the angle α should be appropriately selected so that this area Y is not too small.
Furthermore, if the glass substrate is laminated glass comprising a first glass 2a (outside the vehicle) and a second glass 2b (inside the vehicle), the center of the opening 7a of the first glass 2a and the center of the opening 7b of the second glass 2b may be appropriately offset, as shown in Figure 8. With this configuration, it becomes unnecessary to make the openings 7a and 7b excessively large in order to secure the size of the region Y, especially when the angle α is small, thus achieving both high strength and high clarity.

Furthermore, it is preferable that the window member 1 of this embodiment further includes a visible light transmitting region 13 within the light-shielding region 3, the visible light transmittance of which is 70% or more. By including the visible light transmitting region 13, a visible light camera can be mounted to capture images of the outside from that region.
By adding a visible light camera in addition to the far-infrared camera, the information obtained from these two cameras can be combined to recognize information outside the vehicle, contributing to improved accuracy in object recognition. Furthermore, by providing a far-infrared transmission area 6 and a visible light transmission area 13 within the light-shielding area 3, the far-infrared camera and the visible light camera can be mounted in close proximity, reducing the load when processing the data obtained from each camera, and also facilitating the routing of power and signal cables.
The visible light-transmitting region 13 is a region within the light-shielding region 3 that is partially devoid of the light-shielding layer 5.
Furthermore, the window member 1 of this embodiment may also include, for example, a LiDAR or a millimeter-wave radar in addition to the visible light camera.

<Exterior components for vehicles equipped with far-infrared cameras>
Next, the exterior component for a vehicle equipped with a far-infrared camera according to the present invention will be described.
Figure 9 shows a schematic cross-sectional view of one embodiment of the exterior vehicle member with a far-infrared camera of the present invention. The exterior vehicle member with a far-infrared camera 100 according to this embodiment is a window member with a far-infrared camera, in which a far-infrared camera 9 is attached to a window member 1 that is applied to the windshield of a vehicle.
Furthermore, the vehicle exterior member in this embodiment is not limited to a window member applied to the windshield of a vehicle, as described above.

The window member 100 with a far-infrared camera of this embodiment comprises a window member 1 and a far-infrared camera 9. The window member 1 is as described above. The far-infrared camera 9 is attached to the window member 1 so as to be able to capture an external thermal image through the far-infrared transmission area of the window member 1.
The type of far-infrared camera 9 is not particularly limited, and any known far-infrared camera can be used. The far-infrared camera 9 is attached to the window member 1 by, for example, a bracket 14. The far-infrared camera 9 is usually mounted so that the optical axis X is approximately horizontal.

In order to make the image (thermal image) obtained by the far-infrared camera 9 clearer, it is preferable that the temperature of the far-infrared camera 9 be kept constant.
One way to maintain a constant temperature for the far-infrared camera 9 is to improve the thermal insulation of the bracket 14. To improve the thermal insulation of the bracket 14, one can either keep the inside of the bracket 14 under vacuum or fill the inside of the bracket 14 with thermal insulation material. In other words, in the window member 100 with a far-infrared camera of this embodiment, the far-infrared camera 9 is attached to the window member 1 via the bracket 14, and it is preferable that the inside of the bracket 14 is kept under vacuum or filled with thermal insulation material.
Furthermore, as a means of maintaining a constant temperature for the far-infrared camera 9, the temperature inside the bracket 14 can be adjusted using a temperature controller. In other words, in the window member 100 with a far-infrared camera of this embodiment, the far-infrared camera 9 is attached to the window member via the bracket 14, and it is preferable to further provide a temperature controller for adjusting the temperature inside the bracket 14.

Furthermore, if the window member 1 has a visible light transmission region 13, it is preferable that the window member 100 with a far-infrared camera of this embodiment further includes a visible light camera attached to the window member 1 so as to be able to capture images of the outside through the visible light transmission region 13.
By adding a visible light camera in addition to the far infrared camera, as mentioned earlier, the information obtained from these two cameras can be combined to recognize information outside the vehicle.
In this case, it is preferable to make the optical axis of the far-infrared camera and the optical axis of the visible light camera approximately parallel, and to keep the distance between these optical axes 20 cm or less. Note that "approximately parallel" is a concept that includes not only cases where these optical axes are perfectly parallel, but also cases where they are slightly deviated from parallel by an error margin. By doing so, the optical axis of the far-infrared camera and the center of the field of view of the visible light camera almost coincide, which is preferable when combining images obtained from these cameras for information processing.

Furthermore, the visible light camera may be a stereo camera comprising a first camera and a second camera. In this case, it is preferable to place the far-infrared camera between the first camera and the second camera. In this case, it is also preferable that the optical axes of the far-infrared camera, the first camera, and the second camera are all substantially parallel, and that the distance between the optical axes of any of the cameras is 20 cm or less.
Furthermore, in addition to a visible light camera, other sensors such as LiDAR and millimeter-wave radar may also be included. In this case as well, it is preferable to place each sensor in close proximity while suppressing signal interference.

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

<Preparation of far-infrared transmitting material>
Cylindrical far-infrared transmitting members of different sizes (far-infrared transmitting members A to Q) made of Si, Ge, ZnS, or chalcogenide glass were prepared. The material, diameter L, and thickness t of each far-infrared transmitting member are shown in Tables 1 to 3.
The far-infrared transmitting member J was manufactured as follows: First, glass raw materials were mixed to the following atomic percentages: Ga 6.0%, Sb 24.0%, Sn 4.0%, S 62.0%, Cs 2.0%, and Cl 2.0%. This mixture was then sealed in a quartz glass tube with an inner diameter of 25 mm, and the temperature was raised to 750°C for 4 hours to melt it. After that, the molten glass was rapidly cooled and then slowly cooled to obtain an ingot. The ingot, along with the quartz glass tube, was cut and polished to obtain the far-infrared transmitting member J.
Furthermore, the far-infrared transmitting member O had a five-layer anti-reflective coating consisting of Ge, Si, and _YF3 on its outer surface, the far-infrared transmitting member P had a two-layer anti-reflective coating consisting of DLC and Si on its outer surface and a five-layer anti-reflective coating consisting of ZnS and Ge on its inner surface, and the far-infrared transmitting member Q had a one-layer anti-reflective coating consisting of DLC on its outer surface and a two-layer anti-reflective coating consisting of ZnS and Ge on its inner surface, all applied by vapor deposition.

<Measurement of average transmittance of far-infrared rays with wavelengths of 8-13 μm>
The infrared transmission spectra of each far-infrared transmitting material were measured using a Fourier transform infrared spectrometer (ThermoScientific, product name: Nicolet iS10), and the average transmittance at wavelengths of 8 to 13 μm was determined from the obtained infrared transmission spectra. The results are shown in Tables 1 and 2. Figure 10 shows the infrared transmission spectra of far-infrared transmitting materials B, D, F, H, I, and J.

<Manufacturing of window components>
(Example 1)
First, a laminated glass was prepared by placing a 0.76 mm thick PVB between two 300 mm x 300 mm thick soda-lime glass sheets. Next, a through-hole with a diameter of 14 mm was formed centered at a point 100 mm away from the center of the laminated glass in the direction of the edge.
Next, using a urethane-based adhesive, the far-infrared transmitting member A was attached to the through-hole so that it was flush with the outer surface, thereby obtaining the window member of Example 1. The urethane-based adhesive was cured by drying at room temperature for 5 days.

(Examples 2 and 3)
Window members for Examples 2 and 3 were obtained in the same manner as in Example 1, except that the diameter of the through-hole was set to 26.5 mm and far-infrared transmitting members B and C were attached, respectively.

(Example 4)
The window component of Example 4 was obtained in the same manner as in Example 3, except that an acrylic adhesive was used. The acrylic adhesive was cured by drying at 120°C for 1 hour, followed by drying at room temperature for 5 days.

(Examples 5-8)
Window members for Examples 5 to 8 were obtained in the same manner as in Example 2, except that far-infrared transmitting members D to G were attached to each.

(Example 9)
The window component of Example 9 was obtained in the same manner as in Example 8, except that an acrylic adhesive was used. The acrylic adhesive was cured by drying at 120°C for 1 hour, followed by drying at room temperature for 5 days.

(Examples 10-13)
Window members for Examples 10 to 13 were obtained in the same manner as in Example 2, except that far-infrared transmitting members H to K were attached to each.

(Examples 14, 15)
Window members for Examples 14 and 15 were obtained in the same manner as in Example 1, except that the diameter of the through-hole was set to 51.5 mm and far-infrared transmitting members L and M were attached, respectively.

(Example 16)
The window member of Example 16 was obtained in the same manner as in Example 1, except that the diameter of the through hole was set to 91.5 mm and a far-infrared transmitting member N was attached.

(Examples 17-19)
Window members for Examples 17 to 19 were obtained in the same manner as in Example 1, except that the diameter of the through-hole was set to 51.5 mm and far-infrared transmitting members O, P, and Q were attached, respectively.

<Evaluation of ball drop strength>
Using window components from Examples 1 to 19, the following ball-fall strength evaluations 1 and 2 were performed. Components that passed both tests were marked with "○", while those that failed either test were marked with "×". The evaluation results are shown in Tables 1 and 2. (Ball-fall strength evaluation 1)
The evaluation was conducted using a ball-dropping device and support frame that conformed to the impact resistance test specified in JIS R3211, 3212-2015.
First, the window component was kept in a room maintained at a temperature of 23°C and relative humidity of 50% for 4 hours, and then fixed with a support frame so that the outer surface was facing upward. Next, a 226g steel ball was dropped onto the center of the window component from a height of 10m. The test was considered successful if the steel ball did not penetrate the window component and the total mass of the detached fragments from the opposite side of the impact surface was 15g or less. (Ball Drop Strength Evaluation 2)
The test was conducted in the same manner as in Ball Drop Strength Evaluation 1, except that a 509g steel ball was used. The test was considered successful if the far-infrared transmitting member did not break or detach from the window member, and the total mass of the detached fragments from the opposite side of the impact surface was 15g or less.

<Thermal Image Visual Evaluation>
The following thermal image visualization evaluation was performed using window members from Examples 1 to 19.
First, the window component was positioned so that its angle from the horizontal plane was α. Next, the far-infrared camera (Wuhan Guide Infrared, Cube 417 (resolution: 400 x 300, horizontal field of view: 20°, vertical field of view: 15°, focal length: 19 mm)) was positioned so that its optical axis was horizontal and centered on the far-infrared transmitting component, and was placed so close that its housing was in contact with the window component.
Next, at an ambient temperature of 26°C, a pedestrian positioned 100m from a window was photographed using a far-infrared camera, as shown in Figure 11. From the obtained thermal image, a 20x30 pixel area centered on the pedestrian was extracted, and the thermal image contrast was evaluated by "maximum brightness / minimum brightness" through image analysis. A higher thermal image contrast value indicates a clearer image. A thermal image contrast value of 3.0 or higher indicates that a pedestrian 100m away can be sufficiently recognized.
The window member in Example 1 was tested at α = 30°, 60°, and 90°.
The window members in Examples 2, 5, 7, 10, 12, 13, and 19 were tested at α = 30° and 45°.
Window members in Examples 3, 6, 8, 11, and 14-18 were tested at α = 30°.
Note that Examples 4 and 9 differ from Examples 3 and 8 only in the type of adhesive used, and the results of the thermal image visualization evaluation are expected to be the same as those of Examples 3 and 8, therefore no tests were conducted on them.
Tables 1 and 2 show the values of α, the diameter R of the largest circle formed inside the projection diagram obtained by projecting a far-infrared transmitting member in the optical axis direction, and the thermal image contrast values.
Figure 12 also shows thermal images of pedestrians extracted in Example 1 (α = 30° and 60°), Example 5 (α = 30°), Example 10 (α = 30° and 45°), Example 12 (α = 30°), Example 13 (α = 30°), and Example 15 (α = 30°).

The results of the ball drop strength evaluation for each case are described below.
Examples 2, 7, and 14, which used far-infrared transmitting members B, F, and L with a thickness t of 1 mm, showed insufficient strength.
Furthermore, in example 16, which used a far-infrared transmitting member N with a thickness t of 3 mm but a diameter L of 90 mm, the strength was also insufficient.
On the other hand, Examples 1, 3-6, 8-13, 15, and 17-19, which used far-infrared transmitting members A, C-E, G-K, M, and O-Q having a thickness t of 1.5 mm or more and a diameter L of 80 mm or less, exhibited sufficiently high strength.

Furthermore, the results of the thermal image visualization evaluation for each example are described below.
In the α = 30° and 60° tests of Example 1, where R was 6.3 mm and 10.8 mm respectively, sufficient thermal image contrast was not obtained, and the clarity of the thermal image was low, as shown in Figure 12. On the other hand, in the α = 90° test of Example 1, where R was 12.5 mm, sufficient thermal image contrast was obtained.
In the test of Example 6, which used far-infrared transmitting material E with an average transmittance of 14% for far-infrared rays with wavelengths of 8 to 13 μm, sufficient thermal image contrast could not be obtained.
In the tests for Examples 2, 3, 5, 7, 8, and 10-19, where R was 12 mm or more and the average transmittance of far-infrared rays with wavelengths of 8-13 μm was 25% or more, sufficient thermal image contrast was obtained in all cases.

As is clear from the results above, far-infrared transmitting members with a thickness t of 1.5 mm or more, a diameter L of 80 mm or less, an average transmittance of far-infrared rays with wavelengths of 8 to 13 μm of 25% or more, and a diameter R of the largest circle formed inside the projection diagram obtained by projecting the far-infrared transmitting member in the direction of the optical axis of 12 mm or more exhibited both high intensity and sufficient thermal image contrast.
This international application claims priority based on Japanese Patent Application No. 2019-136326, filed on 24 July 2019, and the entire contents of Japanese Patent Application No. 2019-136326 are incorporated herein by reference.

1. Vehicle exterior component (window component); 2. Glass substrate; 2a. First glass; 2b. Second glass; 3. Light-shielding region; 4. Light-transmitting region; 5. Light-shielding layer; 6. Far-infrared transmission region; 7. Opening; 7a. Opening of the first glass; 7b. Opening of the second glass; 8. Far-infrared transmission component; 9. Far-infrared camera; 10. Projection surface; 11. Projection diagram; 12. The largest circle formed inside the projection diagram; 13. Visible light transmission region; 14. Bracket; 15. Intermediate layer; 100. Window component with far-infrared camera; X-axis

Claims (10)

A vehicle exterior component having a light-shielding area, which is attached to a vehicle equipped with a far-infrared camera and a visible-light camera ,
Vehicle exterior components are vehicle window components that are attached to the vehicle so that their inclination with respect to the horizontal direction is 60° or less.
The light-shielding region further comprises a far-infrared transmitting region having an opening and a far-infrared transmitting member disposed within the opening,
The far-infrared transmitting member has an average transmittance of 25% or more of far-infrared rays with wavelengths of 8 to 13 μm, and the length of the longest straight line connecting any two points on the outer surface of the far-infrared transmitting member is 80 mm or less.
The diameter of the largest circle formed inside the projection diagram obtained by projecting the far-infrared transmitting member in the optical axis direction of the far-infrared camera is 12 mm or more, and the average thickness of the far-infrared transmitting member is 1.5 mm or more.
At least one of the outer surface and the inner surface of the far-infrared transmitting member is provided with 1 to 12 layers of anti-reflective coating.
The light-shielding region further comprises a visible light-transmitting region having a visible light transmittance of 70% or more .
The far-infrared camera is mounted on the vehicle exterior member so as to be able to capture an external thermal image through the far-infrared transmitting member, and the visible light camera is mounted on the vehicle exterior member so as to be able to capture an external image through the visible light transmitting region, and the optical axis of the far-infrared camera and the optical axis of the visible light camera are substantially parallel, and the distance between these optical axes is 20 cm or less.
Vehicle exterior components. The vehicle exterior member according to claim 1, wherein the far-infrared transmitting member is made of at least one material selected from the group consisting of ZnS, Ge, Si, and chalcogenide glass. The exterior component for a vehicle according to claim 1 or 2, wherein the outermost layer of the anti-reflective coating is a diamond-like carbon film. The exterior surface of the far-infrared transmitting member is formed flush with the exterior surface of the light-shielding region, as described in claim 1 or 2. The vehicle exterior member according to claim 1 or 2, wherein the far-infrared transmitting member is attached with a urethane-based adhesive and/or an acrylic-based adhesive. The longest straight line connecting any two points on the outer surface of the far-infrared transmitting member is 65 mm or less.
Vehicle exterior member according to claim 1 or claim 2. The area of the opening on the interior side of the vehicle is smaller than the area on the exterior side of the vehicle.
The far-infrared transmitting member has an area on the inner surface of the vehicle that is smaller than the area on the outer surface of the vehicle.
Vehicle exterior member according to claim 1 or claim 2. The vehicle exterior member according to claim 1 or 2, wherein the visible light camera is a stereo camera comprising a first camera and a second camera, and the far infrared camera is located between the first camera and the second camera. The vehicle exterior member according to claim 1 or claim 2, wherein the far-infrared camera is attached to the vehicle exterior member via a bracket, and the inside of the bracket is kept under vacuum or filled with heat insulating material. The vehicle exterior member according to claim 1 or 2, wherein the far-infrared camera is attached to the vehicle exterior member via a bracket, and further comprises a temperature controller for adjusting the temperature inside the bracket.